Optimized telecommunications distribution system

ABSTRACT

Systems and methods for optimized telecommunications distribution are provided. For example, a distributed antenna system can include a master unit for transceiving signals with remote units operable for wirelessly transceiving signals with mobile devices in a coverage area. A self-optimized network analyzer can be in a unit of the distributed antenna system. A self-optimized network controller in the distributed antenna system can output commands for changing operation of a component in the distributed antenna system in response to analysis results from the self-optimized network analyzer. In some aspects, the master unit includes base transceiver station cards for receiving call information in network protocol data from a network and for generating digital signals including the call information from the network protocol data for distribution to the remote units.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. Non-Provisional patent application Ser.No. 13/757,742 filed Feb. 2, 2013 and titled “OptimizedTelecommunications Distribution System, which claims priority to U.S.Provisional Application Ser. No. 61/594,085 filed Feb. 2, 2012 andtitled “Multi-Base Station with Configurable Distribution Using ActiveAntennas,” the contents of both of which are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates generally to telecommunications and, moreparticularly (although not necessarily exclusively), to optimizedsystems for distributing telecommunications signals.

BACKGROUND

A distributed antenna system (“DAS”) can be used to extend the coverageof a cellular communication system to areas of traditionally low signalcoverage, such as within buildings, tunnels, or in areas obstructed byterrain features. A DAS can extend coverage by receiving signals from abase station of a cellular communication system and re-transmitting thesignals directly into low-coverage areas. A DAS can include a masterunit distributing signals to, and receiving signals from, remote antennaunits that are physically separate from the master unit, but incommunication with the master unit over a link. A remote antenna unitcan wirelessly communicate signals to wireless devices positioned in acoverage area.

Optimized DAS's and/or DAS's having base transceiver stationcapabilities are desirable.

SUMMARY

In one aspect, a distributed antenna system is provided that includes amaster unit, a self-optimized network analyzer, and a self-optimizednetwork controller. The master unit can transceive signals with remoteunits that can wirelessly transceive signals with mobile devices in acoverage area. The self-optimized network analyzer is in a unit of thedistributed antenna system. The self-optimized network controller canoutput commands for changing operation of a component in the distributedantenna system in response to analysis results from the self-optimizednetwork analyzer.

In another aspect, a distributed antenna system is provided thatincludes a master unit. The master unit can communicate digitizedsignals with remote units operable for providing wireless networkcoverage in an area. The master unit includes base transceiver stationcards that can receive call information in network protocol data from anetwork and that can generate digital signals including the callinformation from the network protocol data for distribution to theremote units.

In another aspect, a distributed antenna system is provided thatincludes a master unit, a self-optimized network analyzer, and aself-optimized network controller. The master unit can communicatedigitized signals with remote units operable for providing wirelessnetwork coverage in an area. The master unit includes base transceiverstation cards that can receive call information in network protocol datafrom a network and that can generate digital signals including the callinformation from the network protocol data for distribution to theremote units. The self-optimized network analyzer is in a unit of thedistributed antenna system. The self-optimized network controller is inthe master unit and can output commands for changing operation of acomponent in the distributed antenna system in response to analysisresults from the self-optimized network analyzer.

The details of one or more aspects and examples are set forth in theaccompanying drawings and the description below. Other features andaspects will become apparent from the description, the drawings, and theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example of a distributed antenna system.

FIG. 2 is a block diagram of an example of a self-optimized networkcontroller.

FIG. 3 is a block diagram of an example of a self-optimized networkanalyzer.

FIG. 4 is a flow chart of an example of a process for optimizing adistributed antenna system based on interference in a downlink band.

FIG. 5 is a flow chart of an example of a process for selecting channelsto use in a distributed antenna system.

FIG. 6 is a block diagram of an example of a multi-base transceiverstation distributed antenna system.

FIG. 7 is a block diagram of the multi-base transceiver stationdistributed antenna system of FIG. 6 in communication with a basestation controller according to one example.

FIG. 8 is a block diagram of a master unit of the multi-base transceiverstation distributed antenna system of FIG. 7 in communication with aswitch according to one example.

DETAILED DESCRIPTION

Certain aspects and examples of the present invention are directed to adistributed antenna system (“DAS”) that is optimized. In some aspects, aDAS includes self-optimized network (“SON”) capabilities, also referredto as self-organizing network capabilities or self-organized networkcapabilities. SON capabilities can include, among others, detectinginterference in a downlink band and modifying transmission of signals inthe downlink band, identifying free frequencies by analyzing frequenciesused in a macro-cell environment, and storing information aboutfrequencies using in a macro-cell environment. SON capabilities can useless centralized network planning and employ algorithms that can, forexample, identify the locally used frequencies and determine thefrequencies for a new base station transceiver (“BTS”) from the resultsof the algorithms. Local or remote databases can be used to support thealgorithms. The algorithms can minimize the amount of interferencecreated and experienced by new BTS signals.

In some aspects, the DAS is a multi-base transceiver station DAS(“MB-DAS”). The MB-DAS may include the SON capabilities and/oradditional SON capabilities, or no SON capabilities. The MB-DAS caninclude one or more BTS cards. The BTS cards can encode signals, decodesignals, process signals into a proper wireless protocol, communicatesignals to a BTS controller or mobile telephone switching office, andprovide processed signals for digital distribution to distributedantennas in a coverage area. In some aspects, a MB-DAS can distributesignals without requiring installation or use of a conventional BTS. TheBTS cards can be easily added, removed, or replaced to provide desiredwireless communication protocol transmission and allow capacity to beeasily configurable. An MB-DAS, according some aspects, may includeadditional SON capabilities, such as synchronization in frequency and intiming among BTS cards, macro-cell to DAS-cell hand-in configuration,DAS-cell to macro-cell hand-off configuration, maintenance of macro-celland DAS-cell database information, and mapping of antenna units withmacro-cell hand-off and hand-in support. Although “BTS” and “MB-DAS” areused herein, NodeB (e.g., for 3G-UMTS wireless networks) and/or eNodeB(e.g., for 4G LTE) can additionally or alternatively be used.

FIG. 1 depicts an example of a DAS 110 in communication with one or morebase stations 112 a-n, which may be base transceiver stations. The DAS110 can include a master unit 114, remote units 116 a-d, and anextension unit 118. The DAS 110 may be positioned in an area of lowsignal coverage, such as the interior of a building, to extend wirelesscommunication coverage. Extending wireless coverage can includecommunicating signals between base stations 112 a-n and wireless devicespositioned in a coverage area of the DAS 110.

The master unit 114 can receive downlink signals from one or more basestations 112 a-n via a wired or wireless communication medium. Themaster unit 114 can also provide uplink signals to the base stations 112a-n.

The master unit 114 can communicate uplink and downlink signals betweenthe base stations 112 a-n and one or more remote units 116 a-ddistributed in the environment to provide coverage within a service areaof the DAS 110.

The master unit 114 can convert downlink signals received from the basestations 112 a-n, such as RF signals, into one or more digital datastreams. A group of signals represented by digital data streams can forma band set. The master unit 114 can include circuitry, such as summersor multiplexers, configured to combine the digital data streams within aband set into a band stream. The band stream may be a single digitaldata stream that includes the digital data streams representing thesignals in a band set. In some aspects, combining the digital datastreams can include summing or adding signals within a band set. Inother aspects, combining the digital data streams can includemultiplexing the digital data streams into a serialized band stream.

The master unit 114 can provide downlink signals, such as digital datastreams, to some of the remote units, such as remote units 116 a-b viaan extension unit 118. A non-limiting example of an extension unit is atransport extension node. The extension unit 118 can extend the range ofthe master unit 114. A master unit 114 may transmit optical downlinksignals over an optical fiber link to extension unit 118. The extensionunit 118 can convert the optical downlink signals to electrical downlinksignals and provide the electrical downlink signals to remote units 116a-b over a copper cable, such as a coaxial cable, or other suitablecommunication medium.

The master unit 114 can also directly provide downlink signals to theremote units, such as remote units 116 c-d. Directly providing downlinksignals can include, for example, communicating the downlink signalsfrom the master unit 114 to the remote units 116 c-d without thedownlink signals being received by a separate communication device, suchas a transport extension node or other device, in the signal pathbetween the master unit 114 and a remote unit.

The remote units 116 a-d can convert digital data streams to RF signals.The remote units 116 a-d can amplify the downlink signals and radiatethe downlink signals using antennas to a number of different wirelessdevices, such as (but not limited to) cellular phones, operating in theenvironment of the DAS 110. A non-limiting example of a remote unit is auniversal access point.

In an uplink direction, the remote units 116 a-d can receive uplink RFsignals, convert them to digital data streams, and provide the uplinkdigital data streams to the master unit 114 or the extension unit 118.The extension unit 118 can combine uplink digital data streams intocombined digital data streams, such as band streams, and provide thecombined digital data streams to the master unit 114. In some aspects,the master unit 114 can convert uplink digital data streams receivedfrom the remote units 116 a-d and/or the extension unit 118 into uplinkRF signals. The master unit 114 can provide the uplink RF signals to thebase stations 112 a-n. In other aspects, the master unit 114 can convertuplink digital data streams received from the remote units 116 a-d intodigital signals formatted for transmission to the base stations 112 a-nthat communicate using digital signals, in a standardized digital formator otherwise.

The master unit 114, extension unit 118, and remote units 116 a-d cancommunicate via communication transport links. A communication transportlink can include one or a series of physical connections over which aremote unit can communicate with the master unit 114 directly or throughthe extension unit 118. A communication transport link can include anytype of communication medium capable of transporting signals between themaster unit 114, the extension unit 118, and/or the remote units 116a-d.

Although the DAS 110 is depicted as including one master unit 114, oneextension unit 118, and four remote units 116 a-d, any number (includingone) of each can be used. For example, a DAS 110 may include dozens ofextension units and hundreds of remote antenna units.

The DAS 110 can also include SON components, such as SON controller 120and one or more SON analyzers 122 a-c. The SON controller 120 is shownas being located in the master unit 114, but the SON controller 120 canbe located in other components of the DAS 110, as a separate componentof the DAS 110, or in a device external to the DAS 110. In some aspects,the DAS includes one SON analyzer located in a component of a DAS.

Each of the SON analyzers 122 a-c may be capture and analysissub-systems that can analyze signals or other information associatedwith the DAS 110 and provide analysis results to the SON controller 120.The SON controller 120 can output commands for changing operation of acomponent in the DAS 110 in response to the analysis results and/orinformation stored locally or stored remotely, such as in a databasedevice 124 in communication with the master unit 114 but remote from theDAS 110.

DAS 110 may provide mobile telecommunication coverage for an area and belocated close to macrocell coverage areas, such as areas serviced bymacrocell base station 126 a by a first carrier, macrocell base station126 b by a second carrier, and macrocell base station 126 c by a firstcarrier.

FIG. 2 depicts an example of the SON controller 120. Otherconfigurations and examples may, of course, be utilized. The SONcontroller 120 may be any device that can process data and execute codethat is a set of instructions to perform actions. The SON controller 120includes a processor 202, a memory 204, a bus 206, and an input/output(I/O) interface 208. The memory 204 includes a controller engine 210 anda data store 212.

The processor 202 can execute code stored on a computer-readable medium,such as the memory 204, to cause the SON controller 120 determine acommand and output the command to change operation of a component of aDAS. Non-limiting examples of a processor 202 include a microprocessor,an application-specific integrated circuit (“ASIC”), afield-programmable Gate Array (“FPGA”), or other suitable processor. Theprocessor 202 may include one processor or any number of processors.

The processor 202 can access code stored in the memory 204 via a bus206. Memory 204 may be any non-transitory computer-readable mediumcapable of tangibly embodying code and can include electronic, magnetic,or optical devices. Non-limiting examples of a memory 204 include randomaccess memory (RAM), read-only memory (ROM), magnetic disk, an ASIC, aconfigured processor, or other storage device. Bus 206 may be any devicecapable of transferring data between components of the SON controller120. Bus 206 can include one device or multiple devices. Instructionscan be stored in the memory 204 as executable code. The instructions caninclude processor-specific instructions generated by a compiler and/oran interpreter from code written in any suitable computer-programminglanguage.

The controller engine 210 can receive through an I/O interface 208inputs such as analysis results from one or more of the SON analyzers122 a-c and information from database device 124 in FIG. 1. Thecontroller engine 210 can also cause data to be stored in data store 212and access the data in data store 212. For example, the controllerengine 210 can store a history of measurements and use the storedhistory of measurements to perform DAS configuration changes at a laterdate.

FIG. 3 depicts an example of a SON analyzer 122. Other configurationsand examples may, of course, be utilized. The SON analyzer 122 issimilar to the SON controller 120 of FIG. 2 and may be any device thatcan process data and execute code that is a set of instructions toperform actions. The SON analyzer 122 includes a processor 302, a memory304, a bus 306, and an input/output (I/O) interface 308. The memory 304includes an analyzer engine 310 and a data store 312.

The processor 302 can be similar to the processor 202 of FIG. 2 and canexecute code stored on a computer-readable medium, such as the memory304, to cause the SON analyzer 122 to receive signals and information,analyze the signals and information, and output analysis results. Theprocessor 302 can access code stored in the memory 304 via a bus 306.Memory 304 can be similar to memory 204 of FIG. 2, and may be anynon-transitory computer-readable medium capable of tangibly embodyingcode and can include electronic, magnetic, or optical devices. Bus 306may be any device capable of transferring data between components of theSON analyzer 122.

The analyzer engine 310 can receive through an I/O interface 308 inputssuch as signals and information from the DAS 110, analyze the signalsand information, and provide the analysis results through the I/Ointerface 308 for receipt by the SON controller 120. In some aspects,the analyzer engine 310 can be triggered to analyze signals or otherinformation based on a command from a SON controller or a deviceexternal to the DAS 110.

Examples of SON Capabilities

A DAS according to some aspects, can be located close to (or in somecases in) an environment served by a macrocell. Signals from themacrocell may be strong enough to interfere with one or more signalstransmitted by a remote unit of the DAS. For example, macrocellinterface may be caused by signals in a downlink band in which theremote unit also transmits signals. There may also be sources ofinterference other than a macrocell. The SON controller 120 and SONanalyzer 122 can detect and measure sources of interference in an uplink(e.g., a signal path from a mobile device to the master unit 114) bandand/or a downlink (e.g., a signal path from the master unit 114 to themobile device) band and modify operation of the DAS 110 in response tothat analysis. FIG. 4 is a flow chart that depicts one example fordetecting interference in a downlink band and modifying operation of theDAS 110.

In block 402, the SON controller 120 outputs a command for preventingthe DAS 110 from transmitting signals in a selected downlink band by aremote unit, such as one of the remote units 116 a-d, a subset of theremote units 116 a-d, or all of the remote units 116 a-d. The downlinkband can be selected in the order of downlink bands being transmitted bythe DAS 110, a list of potential macrocell bands, or otherwise.

In block 404, the SON controller 120 sends a command to tune a receiverin the remote unit to receive signals in the downlink band. Receivers inremote units 116 a-d can be tuned to selected uplink bands for the DASto receive signals from mobile devices in a coverage area. The receivercan respond to the command from the SON controller 120 by changingoperation to receive the downlink band rather than the uplink band.

Signals in the downlink band can be received by the remote unit. Inblock 406, a SON analyzer 122 located in the remote unit, in theextension unit 118, or in the master unit 114, processes the signalsreceived in the downlink band. In some aspects, the signals aredigitized and processed by the SON analyzer 122 to detect RF power inthe downlink band, detect the power of individual RF channels in thedownlink band, determine the modulation type of the channel, and decodeinformation on the detected channel. The SON analyzer 122 can send theanalysis results to the SON controller 120. In some aspects, the SONanalyzer 122 analyzes the signal power level of the pilot signal insteadof the composite signal level, which can depend on traffic level, ineach channel, portion of a channel, or multiple portions of the downlinkband.

In block 408, the SON controller 120 determines, based on the analysisresults, whether the received signals are above an interferencethreshold. The interference threshold may be a pre-set threshold that isdefined by the user of the DAS 110 or pre-defined within the DAS 110during manufacturing. The interference threshold may be stored locallyor remotely and accessed by the SON controller 120.

If the received signals are not above the interference threshold, theSON controller 120 sends a command to resume transmission of DAS signalsin the downlink band and causes the receiver to be re-tuned to theuplink band instead of the downlink band, in block 410. The command maybe sent to one or more components of the master unit 114 and/or a remoteunit. If the received signals are above the interference threshold, theSON controller 120 sends a command to modify transmission of signals inthe downlink band, in block 412. For example, the SON controller 120 cancause the gain applied to the signals in the downlink band to increaseand cause the receiver to be re-tuned to the uplink band rather than thedownlink band. If the received signals are significantly above theinterference threshold, the SON controller 120 can cause downlinksignals to be transmitted in a different downlink band or a differentportion of the downlink band.

The measurement and enabling/disabling of signal transmission by theremote unit can be performed upon user command, automatically duringinitial commissioning, or automatically scheduled during times that areleast likely to impact system interference (e.g., during nighttimehours). If performed automatically at certain intervals, hysteresis canbe used to prevent frequent enabling/disabling of signals at a remoteunit. In addition, a history of past measurements can be stored for theremote unit and the history can be used to evaluate whether to enable ordisable the signal at the remote unit. In other aspects, a remote unitcan include a dedicated receiver for downlink bands rather than tuning areceiver normally used for uplink signal reception. In addition oralternatively, this process can be used to measure transmit power byneighboring remote units as received by a particular remote unit and toadjust the power level of each remote unit in the case of multiplefactors.

SON capabilities can include selecting channels for use in the DAS 110.FIG. 5 depicts an example of a process for doing so. In block 502,signals from a macro-cell environment are received by a SON analyzer122. In some aspects, the SON analyzer 122 can perform received signalstrength indication (RSSI) of the wireless bands to identify activechannels within the wireless bands. The number of channels can beestimated from the centers of RSSI energy. Local or remote databaseinformation can be used to determine on which frequency to expect awireless communication channel. A potential macro-cell channel candidatelist that is sorted according to the RSSI strength and the channelbandwidth can be maintained for a predetermined depth. In addition, asecond list of channels where no significant activity has been detectedcan be maintained as a list of potential DAS-cell channel candidates.This list can be sorted according to the RSSI level or the change fromthe noise level and its available bandwidth, ranking the entry thehighest that has the lowest RSSI and the highest bandwidth.

In some aspects, the SON controller 120 can initiate the scan of the SONanalyzer 122 of wireless communication bands to measure RSSI and decodeidentified signals present in the coverage area of the DAS. The scanningcan be performed by tuning the receive section of one or more of theremote units 116 a-d to downlink frequencies or bands. Transmit portionsof the remote unit used for scanning (and potentially one or moreadjacent remote units) can be caused by the SON controller 120 totemporarily pause transmission during scanning. Scanning can beperformed on all bands or just a subset of bands, and can beperiodically repeated.

In block 504, the SON analyzer 122 processes the signals from themacro-cell environment. For example, the SON analyzer 122 canperiodically decode the signals from the potential macro-cell channelcandidate list and determine parameters, such as the absolute frequencyof the decoded channel with respect to the internal frequency reference,the timing offset to the internal timing reference, the absolute timingsuch as the frame number, and key network parameter such as MobileCountry Code, Mobile Network Code, Cell ID, Location Area Code, list ofneighbor cells, etc. The SON controller 120 can maintain the results ina database.

In block 506, the SON controller 120 receives database informationstored locally or remotely in database device 124 or otherwise. Thedatabase information can include the parameters and/or other types ofinformation related to the macrocell and DAS. For example, the databaseinformation can include scanning results for each remote unitindividually or on a per operator basis, identification of a comment setof cells according to signal strengths and presence counted in eachremote unit, and/or cell parameters (e.g., for GSM network, MCC, MNC,CellID, LAC, BSID, and Neighbor Cells). In some aspects, the databaseinformation includes a location of the DAS system. For example, the SONcontroller 120 can determine the location of the DAS system usinguser-configured location data, GPS receiver data, macro-celltrilateration functions, macro-cell system location information (CellIDor the location coordinates when transmitted), and/or map data, such asdata from GOOGLE MAPS™. The SON controller 120 can use the informationto determine the position of a mobile device from the presence of thewireless carriers received by the device. The SON controller 120 mayalso determine and store the assigned frequencies for each operator thatis planned to be assigned to the DAS 110 using the determined locationand/or information from public databases, private databases, the FCCdatabase or information published by the European Communications Office.Map information to determine the boundaries of the assigned frequenciescan also be retrieved from local or remote databases.

The SON controller 120 can determine whether the operator has assigned apreferred channel or set of channels to be used for a SON-type networkfrom database information. As an alternative, the channel or set ofchannels present in the neighbor list of the detected macro-cell signalsthat do not show any RSSI activity may be used.

In block 508, the SON controller 120 selects channels for use in the DAS110 based on the processed signals from the macro-cell environment anddatabase information. For example, the SON controller 120 can analyzethe list of potential DAS-cell channel candidates and select channelsthat are preferred, have the lowest RSSI, or have the highest distancein frequency to high RSSI channels. The SON controller 120 can outputcommands to components of the DAS 110 to configure the components totransmit and/or receive the selected channels. For frequency and timingsynchronization, the SON controller 120 can use the strongest receivedchannel from one operator. If the frequency and timing is different forsignals in different RF bands for the same operator, the SON controller120 can maintain synchronicity with signals from both bands. A similarprocess can be applied to signals from the same operator employingdifferent standards.

Multi-Base Transceiver Station Distributed Antenna System

A DAS according to some aspects may be an MB-DAS with configurabledistribution that may use active antenna units. The MB-DAS can include acentralized host or master unit housing BTS cards. In other aspects, oneor more remote units of the MB-DAS includes BTS cards that can receivenetwork protocol data, such as internet protocol data, from a host ormaster unit.

BTS cards may be capacity elements that are connected to a networkbackbone via IP-based interfaces. Wireless communication signals can becommunicated to and from the BTS cards via a digital interface ascomplex digital baseband signals or complex digital or real digitalintermediate frequency signals at a relatively low sampling rate. A BTScard may be associated with a single operator or a multiple operator.The BTS card can be dedicated to the generation and decoding of signalsthat are targeted for transmission and reception in a single wirelesscommunication RF band or be dedicated to multiple wireless communicationRF bands. Multiple bands can be communicated to and from the BTS cardusing individual busses for each band or using a multiplexed datainterface.

FIG. 6 depicts one example of an MB-DAS. The MB-DAS includes a masterunit 602 that can transceive IP data with call information 600 over anIP network, and can transceive digital signals with a remote unit 604that can wirelessly transceive RF signals for providing coverage in anenvironment. In some aspects, the remote unit 604 is an active antennaunit. Included in the master unit 602 are one or more BTS cards 606.

The digital wireless downlink signals of each BTS card 606 may bere-sampled, converted to an individual digital IF signal (represented ascomplex or real samples), digitally conditioned, and digitally summed orotherwise combined with other digital downlink signals from BTS cards toa summed digital IF signal stream. Each digital IF signal stream can bedesignated to be transmitted in the same wireless communication RF band.To frequency position the signals of each BTS card 606 within the summeddigital IF stream by the system controller, the target RF centerfrequency of the BTS card signal can be determined. The summed digitalsignal can be multiplexed and framed for transport via a digitalcommunication link to a signal processor board on which it can befurther digitally switched and summed with other summed signal streamsinto a digital zone signal stream. The zone signal stream can bemultiplexed and framed onto a transport stream, which can be a parallelor serial link. In one aspect, the transport stream is a serial digitalstream such as a 10 Gb/s Ethernet data link on an optical fiber or CAT6acable. Alternatively, higher bit rates, such as 40 Gb/s or 100 Gb/s, aswell as lower bit rate connections can be used for the transport. Thetransport stream can be provided to the remote unit 604 directly orthrough an extension unit.

An MB-DAS according to various aspects may or may not include SONcapabilities. FIG. 7 depicts the MB-DAS having SON capabilities. TheMB-DAS includes a master unit 602, remote units 604 a-d, and anextension unit 714. The master unit 602, through the BTS cards 606 a-n,can communicate with a switch 708 that allows for network communicationto the base station controller 712 over an IP backbone 710 via Abis orother interface, such as lu or S1. In other aspects, the MB-DAS includesthe switch 708. In some aspects, the master unit 602 communicates withother components, such as a mobile telephone switching office, directlyinstead of through the base station controller 712. In other aspects,the base station controller 712 is replaced with a radio networkcontroller (“RNC”), for example in a 3G-UMTS network. In still otheraspects, such as in implementations in a 4G LTE network, no BSC, RNC orequivalent is used. Instead, the BTS cards 606 a-n, which would beeNodeB cards, include RNC functionality and can communicate directlywith a core network. It should be noted that in 3G-UMTS and 4G LTE, basestations with neighboring cells can have a direct interconnection thatis lur (for 3G UMTS) or X2 (for 4G LTE).

The master unit 602 can communicate with the remote units 604 a-ddirectly or through the extension unit 714. The extension unit 714 canreceive the transport stream and fan (i.e., distribute) it out tomultiple remote units. The fan out may be performed without any changeto the stream. In systems having multiple master units, the extensionunit 714 may multiplex or digitally sum multiple zone streams fromdifferent transport streams.

A remote unit can receive the transport stream and perform bit & clockrecovery, conversion back to a parallel data stream, de-framing, andde-multiplexing of the zone streams. Each zone stream can be provided toan RF back-end that can convert it from a digital IF signal to an analogRF signal for transmission via an antenna to wireless devices.

In the uplink direction, each of the remote units 604 a-d can receivethe wireless signal from the mobile device and convert the RF signalinto a digital sampled signal represented by either real or complexdigital samples. The uplink digital signals can be in the same orsimilar format as the downlink zone streams, and can be furtherprocessed, filtered, digitally up- or down-converted, re-sampled,amplitude and phase conditioned, digitally summed, multiplexed withother digital signals, and framed and serialized for transport via adigital transport link. The link may connect to the extension unit 714or to the master unit 602. In the extension unit 714 or the master unit602, the serial data stream can be received, bit & clock recovered,converted back to a parallel data stream, de-framed, de-multiplexed,potentially processed, and potentially digitally summed with otherdigital signals from one or more different remote units 604 a-d. Digitalsignals that are digitally summed may be prevented from overlapping inthe frequency spectrum for later separation. Signals can be preventedfrom overlapping by keeping them on different frequencies in theirdigital spectral distribution and positioning or through multiplexingthem with other digital data streams.

The extension unit 714 or the master unit 602 can sum the uplink signalsaccording to the zone distribution matrix and provide them for furtherprocessing, or can send provide them without adding. Before sendinguplink digital signals back to the BTS cards 606 a-n, the zone streammay be digitally conditioned, filtered, converted to an individualdigital (represented as complex or real samples) IF signal, andre-sampled. The sequence of the processes listed does not necessarilyrepresent the sequence of their application to the digital signal.

Included in the master unit 602 is a SON controller 720, which may beconfigured similar to SON controller 120 of FIG. 2, and capable ofoutputting commands for changing operation of the MB-DAS. Remote unit604 d includes a SON analyzer 722 that may be configured similar to SONanalyzer 122 of FIG. 3, and capable of analyzing signals and otherinformation about the MB-DAS and providing analysis results to the SONcontroller 720. In other aspects, each of the other remote units 604a-c, the master unit 602, and/or the extension unit 714 includes a SONanalyzer. The SON controller 720 and SON analyzer 722 can provide SONcapabilities, such as those described previously and additional SONcapabilities.

For example, a remote unit can provide the downlink received signalsfrom the RF environment to support the SON capabilities. Receivingdownlink signals can include tuning the uplink frontend to downlinkfrequencies while the downlink back-end is deactivated. The SON analyzer722 can perform the capture, filtering, frequency conversion,demodulation, decoding, frequency & timing offset determination, anddata extraction. In order to allow the analysis to be performed on oneremote unit, other remote units that would typically be summed togetherwith the signal of the remote unit can be paused for that time period.Alternatively, the capture can be taken at the remote unit or at theinput of the extension unit 714 and transported via a dedicated datatransport link to the unit that includes the SON analyzer 722. The SONcontroller 720 can coordinate the capture and analysis function,retrieve the results from the SON analyzer 722, store it locally orremotely and distribute it to the various elements in the systems.

The SON controller 720 can schedule the monitoring process that cananalyze the downlink spectrum of the relevant wireless network bands. Itcan schedule the deactivation of the downlink path of one or more of theremote units 604 a-d, the tuning of a remote unit receiver to downlinkbands, the capture of samples, the transport to the SON analyzer 722,the processing of the captures, and the presentation of the results.

Another example is synchronization in frequency and in timing. Aninternal clock or alternatively a clock offset to the internal clockdedicated for each operator can be maintained by the SON controller 720and provided to the BTS cards 606 a-n. Each BTS card can generatewireless signals according to the in-synch with the macro-cell network.An absolute timing such as the absolute frame count of the operator canalso be provided. For CDMA signals, a GPS accurate clock may be used.

Another example is macrocell-to-DAS-cell hand-in configuration. To allowhand-in from the macrocell network into the MB-DAS-cell network thechannels used by the MB-DAS-cell can be in the neighbor list of themacro-cell network. This can be from a mobile device user entering theareas of the MB-DAS system with an active data session or a voice call.Having a proper hand-in can transfer the mobile device directly to theMB-DAS-cell and remove the traffic from the macrocell.

A localized broadcast control channel (“BCCH”) generated within themaster unit 602 in one of the BTS cards 606 a-c with limited signalingcan be used to facilitate hand-ins. The BCCH can be on the channel listof the adjacent macro-cells for a hand-in. The localized BCCH can be afully functional BCCH that offers traffic support, or it can be areduced-feature-set BCCH that is used to allow the hand-in from themacrocell and hands the call or data session directly off to adesignated fully functional MB-DAS-cell.

Another example is DAS-cell-to-macrocell hand-off configuration. If auser with a mobile device is leaving the MB-DAS coverage area and intothe macrocell network coverage area, a proper hand-off can be used toallow uninterrupted data and/or voice communication when the transitionis occurring. The macrocell channels can be added to the neighbor celllist in the SON controller 720. The BTS card associated with thehand-off can be connected with the base station controller 712 andmobile switch to support the hand-off.

Another example is mapping of remote units with macrocell hand-off andhand-in support. One feature of an MB-DAS cell network may be to capturethe possible traffic in the confined area and not have the macrocellnetwork be burdened with high-density traffic from the area that theMB-DAS network attempts to cover. Mobile devices operated at the borderof the MB-DAS network can hand-over to the macrocell network if it isexpected that the mobile device will leave the MB-DAS network coveragearea. Therefore, a hand-over can be supported in select areas andomitted in others. For example, remote units close to entrances to thebuilding or structure may be candidates to support hand-in or hand-offto the macrocell network. Entrances that are considered emergency exitsmay be supported as well. Hand-over support in areas with a high numberof transitions between the MB-DAS and the macrocell network can beprovided. Hand-over can be suppressed in other areas, such as windows,where the macrocell network signals may be strong. The suppression canbe achieved by excluding the macrocell channels in the neighbor celllists of the signals radiated in the remote units.

Each of the BTS cards 606 a-n may be a plug-in card capable of beingplugged into a donor card slot using a similar type of interface to abackplane as a donor card. Signals from the BTS cards 606 a-n can bedistributed to remote units digitally. BTS cards 606 a-n can be ahardware implementation or a software implementation using a FPGA or aDSP.

BTS cards 606 a-n can be various types and include variousconfigurations. For example, a BTS card can be a femto, pico, nano, ormicro BTS cards. Femto BTS cards can indicate a low capacity. A pico BTScard can indicate a low-to-medium capacity. A nano BTS card can indicatea medium-to-high capacity. A micro BTS cards can indicate a fullcapacity. A BTS card can be a plug-in BTS resource to plug into thedonor card slot within master unit 602 or extension unit 714. A BTS cardcan be an internal or an external card. A BTS card can combine severalfemto, pico, nano, and/or micro BTS signals into one stream to be sentto a specific number of remote antenna units. BTS cards can be combinedwith donor cards that have either an analog RF interface or a digitalstandardized interface (e.g., CPRI, OBSAI, and ORI) or both. A BTS cardcan have an IP backbone link that may use Ethernet LAN or WAN. A BTScard can use knowledge of the location of the MB-DAS. The location maybe received from a location server, such as a server including acentralized GPS receiver, or the location can be determined bytrilateration of the detected macrocell that is proximate to the MB-DAS.A BTS card can configure cells for the MB-DAS by subdivision orcombining BTS cells on different frequencies to provide increasedcapacity, depending on available free frequencies in the macrocellenvironment.

In some aspects, BTS cards 606 a-n can have an analog IF interface to ananalog DAS that distributes signals in analog form instead of digital.Instead of processing the digital signals, the analog IF signals fromthe BTS cards 606 a-n can be processed (e.g., frequency convertedthrough mixing, filtered, amplified or attenuated, combined with othersignals or provided through a splitter, transported via an analog linksuch as coax cable or analog optical RF signal via optical fiber,amplified and radiated via passive or active antenna units.

FIG. 8 depicts an example of part of the master unit 602 incommunication with the switch 708. The master unit 602 includes amultiplexer/de-multiplexer 850, a backplane 852, a summer 854, areference clock distribution component 856, and a system controller 858.Also depicted are BTS cards 606 a-n, certain details according to someaspects are shown.

For example, each of the BTS cards 606 a-n can include a BTS processordevice such as BTS chipset 860, resample devices 862, 864, frequencytranslation components 866, 868, and digital gain components 870, 872.In a downlink direction (i.e., toward a wireless device), each of theBTS chipsets 860 a-n can receive data from the IP switch 708 as internetprotocol data, or data in another network protocol. The BTS chipsets 860a-n can decode the data, convert the data to an appropriate wirelesscommunication protocol, digitize the data, and modulate the digitizeddata. The modulated digital data can be resampled by resampler devices862 a-n to, for example, increase the sample rate of the modulateddigital data. In other aspects, resampler devices 862 a-n are not used,or the resampler devices 862 a-n resample at the same rate by which thedigitized data was generated. The modulated digital data can be providedto frequency translation components 866 a-n that, using a localoscillator 874 a-n (a numerically controlled oscillator (NCO), forexample, as depicted in FIG. 8), can move the modulated digital data infrequency, up or down, such that the modulated digital data is centeredaround a certain frequency. Moving the modulated digital data to adifferent frequency can facilitate summing or otherwise combining themodulated digital data with modulated digital data from other BTS cards.

Gain may be applied to the modulated digital data by digital gaincomponents 870 a-n. Digital gain may be used to level each of the datasignals prior to summing. The digital interface may use all the bitsavailable to represent the digital signal. For example, if the bit widthof the signal is sixteen bits, the signal level can traverse the sixteenbits to represent the signal amplitude. The signals from a BTS card canbe scaled such that when the signals are combined with signals fromother BTS cards, the signals will not clip the output of the summer. Forexample, if two signals are combined, the BTS signals may be reduced by½ prior to summing. If four BTS cards are summed, the signal can bereduced by ¼ prior to summing. The depth of the bit width of the outputsignal can be increased to avoid the loss of dynamic range. For example,the bit width may be increased by at least one bit for summing twosignals.

Another use of the digital gain may be to control the level of the BTSBCCH (or pilot channel, beacon, or equivalent) in the downlink directionto control handover areas between two MB-DAS cells, each associated withone BTS card. The wireless device can measure BCCH (or equivalent)signal level to determine which BTS to which to lock. The signal levelof the BCCH can be controlled to move the handover region away from hightraffic areas when there is overlapping BTS coverage, such as inbuilding entrances, lobbies, and elevators. The signal level of the BCCHcan be controlled with the digital gain in the downlink direction tocontrol which BTS card a wireless device locks to and to preventhandovers in high traffic areas.

The uplink and downlink gain can be adjusted to be equal so any gainadjustment performed to the downlink signal of a BTS card can beperformed to the uplink path with the same amount of gain. In otherembodiments, no gain is applied.

The modulated digital data from a BTS card can be provided directly tothe multiplexer/de-multiplexer 850, provided to a summer 854 fordigitally summing the modulated digital data with modulated digital datafrom one or more other BTS cards prior to being provided to themultiplexer/de-multiplexer 850, or both. The multiplexer/de-multiplexer850 can multiplex the data into a serialized digital data stream that isprovided to a backplane for digital transport to one or more remoteunits. The remote units, such as remote units 604 a-d of FIG. 7, canconvert the modulated digitized data to analog RF, amplify the analogRF, and cause the analog RF to be radiated by one or more antennaelements for receipt by wireless devices in a coverage area.

In the uplink direction (i.e., from the wireless devices), a remote unitcan receive analog RF from a wireless device, convert the analog RF todigitized upstream data, and cause the digitized upstream data to betransported to the master unit 602 by multiplexing the data with otherdata to a serial data stream. The backplane 852 of the master unit 602can receive the digitized upstream data and provide it to themultiplexer/de-multiplexer 850. The multiplexer/de-multiplexer 850 cande-multiplex the data and provide it to a proper BTS card. Digital gaincomponents 872 a-n can apply a gain to the digitized upstream data.Frequency translation components 868 a-n, using a local oscillator 876a-n, can change the center frequency (up or down, but typically down) toa different frequency for further processing. The digitized upstreamdata may be resampled by resampler devices 864 a-n to reduce the samplerate, and can be provided to the BTS chipsets 860 a-n. The BTS chipsets860 a-n can demodulate the digitized upstream data, convert it to analogRF, and encode the analog RF into an Internet Protocol. The encoded datacan be provided to the IP switch 708 for transport through an IPbackbone to a base station controller.

The foregoing description of the aspects, including illustratedexamples, of the invention has been presented only for the purpose ofillustration and description and is not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Numerousmodifications, adaptations, and uses thereof will be apparent to thoseskilled in the art without departing from the scope of this invention.

What is claimed is:
 1. A system comprising: a plurality of remote unitsof a distributed antenna system, the plurality of remote unitsconfigured to wirelessly receive uplink signals from mobile devices in acoverage area; and a unit communicatively connectable to the pluralityof remote units, the unit being configured for: instructing a remoteunit of the plurality of remote units to wirelessly receive signals in adownlink band; and sending a command to the remote unit regardingtransmission of downlink signals in the downlink band based on ananalysis of the received signals by a self-optimized network analyzer ina unit of the distributed antenna system.
 2. The system of claim 1,wherein the unit is configured for instructing the remote unit toreceive the signals in the downlink band by sending a command to theremote unit to use a receiver to receive the signals, wherein thereceiver comprises a dedicated receiver configured for monitoringdownlink bands and the remote unit comprises an additional receiverconfigured for monitoring uplink bands.
 3. The system of claim 1,wherein the unit is configured for instructing the remote unit toreceive the signals in the downlink band by sending a command to theremote unit to tune a receiver from an uplink band to the downlink band.4. The system of claim 1, wherein the self-optimized network analyzer isin at least one remote unit of the plurality of remote units.
 5. Thesystem of claim 1, further comprising a self-optimized networkcontroller adapted for selecting channels for use in the distributedantenna system based on database information and signals from amacro-cell environment processed by the self-optimized network analyzer.6. The system of claim 5, wherein the database information used forselecting the channels comprises a location of the system.
 7. The systemof claim 1, wherein the unit is further configured for: receiving callinformation in network protocol data from a network, decoding thenetwork protocol data, and generating digital signals comprising atleast one of complex digital samples and real digital samples from thedecoded network protocol data for distribution to the plurality ofremote units, the digital signals including the call information.
 8. Thesystem of claim 1, wherein the unit comprises a master unit of thedistributed antenna system configured for communicating the downlinksignals from a base station to the plurality of remote units.
 9. Adistributed antenna system, comprising: a plurality of remote unitsoperable for providing wireless network coverage in an area; and amaster unit for communicating digitized signals with the remote units,the master unit configured for: receiving call information in networkprotocol data from a network, decoding the network protocol data, andgenerating digital signals comprising at least one of complex digitalsamples and real digital samples from the decoded network protocol datafor distribution to the plurality of remote units, the digital signalsincluding the call information.
 10. The distributed antenna system ofclaim 9, wherein the network protocol data is internet protocol data,wherein the master unit comprises at least one base station transceiverchipset adapted for decoding the internet protocol data and generatingthe digital signals by: converting the call information to a wirelesscommunication protocol, digitizing the call information converted to thewireless communication protocol, and modulating the digitized callinformation to generate the digital signals.
 11. The distributed antennasystem of claim 10, wherein the master unit further comprises afrequency translation device adapted for frequency shifting themodulated digitized data.
 12. The distributed antenna system of claim10, wherein each of the remote units is adapted for: converting thedigital signals to analog RF signals and causing the analog RF signalsto be radiated at an antenna element; converting uplink analog RFsignals received from a wireless device into uplink digital signals; andmultiplexing the uplink digital signals for transport to the masterunit.
 13. The distributed antenna system of claim 12, wherein the atleast one base station transceiver chipset is adapted for demodulatingthe uplink digital signals, converting the demodulated uplink digitalsignals to uplink analog RF signals, and encoding the analog RF signalsinto uplink network protocol data.
 14. The distributed antenna system ofclaim 12, wherein the master unit further comprises a frequencytranslation device adapted for frequency shifting uplink digital signalsthat are de-multiplexed by the master unit.
 15. The distributed antennasystem of claim 12, wherein the master unit further comprises: a firstresample device adapted for resampling the modulated digitized data; asecond resample device adapted for resampling uplink digital signalsfrom at least one of the remote units; a first digital gain deviceadapted for applying a downlink gain to the modulated digitized data;and a second digital gain device adapted for applying an uplink gain tothe uplink digital signals.
 16. The distributed antenna system of claim9, wherein the master unit is further configured for instructing aremote unit of the distributed antenna system to receive signals in adownlink band; and sending a command to the remote unit regardingtransmission of downlink signals in the downlink band based on ananalysis of the received signals by a self-optimized network analyzer ina unit of the distributed antenna system.
 17. A method comprising:instructing a remote unit of a distributed antenna system to receivesignals in a downlink band, wherein the remote unit receives uplinksignals from mobile devices in a coverage area; and sending a commandfrom a master unit of the distributed antenna system to the remote unitregarding transmission of signals in the downlink band based on ananalysis of the received signals by a self-optimized network analyzer ina unit of the distributed antenna system.
 18. The method of claim 17,wherein instructing the remote unit to receive the signals in thedownlink band comprises configuring a dedicated receiver of the remoteunit for monitoring downlink bands, wherein an additional receiver ofthe remote units monitors uplink bands for the uplink signalssimultaneously with the dedicated receiver monitoring the downlinkbands.
 19. The method of claim 17, wherein instructing the remote unitto receive the signals in the downlink band comprises by sending acommand to the remote unit to tune a receiver from an uplink band to thedownlink band.
 20. The method of claim 17, further comprising selectingchannels for use in the distributed antenna system based on databaseinformation and signals from a macro-cell environment processed by theself-optimized network analyzer.
 21. The method of claim 17, furthercomprising: receiving, by the master unit, call information in networkprotocol data from a network, decoding, by the master unit, the networkprotocol data, and generating, by the master unit, digital signalscomprising at least one of complex digital samples and real digitalsamples from the decoded network protocol data for distribution to aplurality of remote units, the digital signals including the callinformation.